1. Field of the Invention
The present invention relates generally to couplings used to connect sections of conduit, and more particularly to those couplings which may be assembled with a minimum of manual manipulation.
2. Description of Prior Art
In a multitude of industrial and automotive applications, it is often desired to connect sections of conduit to one another for completing a flow circuit for a particular fluid. Such fluids may be water, fuel, air, and the like. A wide variety of conduit couplings have been developed over the years with much success, and it has become fairly easy to find a coupling to suit the needs of a given situation. The most common such devices are: (1) the threaded coupling, which employs a female portion threaded onto a male portion, with or without an elastomeric seal, and (2) a "ball-lock" device, which uses a female body having a spring-loaded sleeve into which a male nipple is locked. In most cases, it is the latter of these two which predominate, because they are easier to use than threaded couplings, result in a strong connection, and enable the opposite conduit ends to swivel in the cases of flexible conduit applications.
In the ball-lock couplings, a male nipple having an external annular groove is inserted into a female coupler body and is locked therein by a plurality of circumferentially spaced balls which engage the groove. A spring-loaded sleeve forces the balls to protrude into the coupler body, such that the sleeve must be pulled backed in order to release the connection. Despite its advantages, several shortcomings are apparent, especially in automotive assembly environments. First, the ball-lock couplings require two hands for making the connection. For example, one hand must grip the female portion and pull back the sleeve with one hand, while the other hand must grip the male nipple and push it into the female portion. In setups where the female portion is fixed relative to the vehicle, one must still grasp the female portion to release the sleeve, preventing the worker from making the connection with only one hand. These time-consuming operations can become very expensive to a manufacturer, because productivity is critically dependent on the time it takes workers to complete these tasks, especially when they are repeated many thousands of times.
Second, such couplings can be accidentally disconnected by inadvertent movement of the sleeve from its locking position, resulting in an additional time to reconnect the coupling and/or fluid loss if the system is functioning. Third, the presence of the external sleeve makes the coupling more bulky than necessary, making it difficult to assemble and disassemble in cramped work spaces. Fourth, the ball-lock devices do not afford a full 360.degree. contact with the male nipple, because the only points of contact are where the limited number of balls touch the groove. Finally, the ball-lock couplings have numerous parts and are relatively expensive to manufacture and install.
What is needed, therefore, is a conduit coupling that can be quickly connected using only one hand, and that is less expensive to produce and operate than its counterparts. Also, such a coupling should achieve these objectives using as few parts as possible, and should be small enough to allow easy manipulation in cramped environments. Ideally, its design should also minimize the possibility of accidental disconnection, but it should still be capable of swiveling to reduce twisting and kinking of flexible conduit. Finally, when the coupling is connected, there should be a strong, uniform 360.degree. contact around the male portion of the coupling to ensure against disengagement.